The present invention relates to a master cylinder and power booster system for vehicle brake apply operation. More particularly, the invention relates to a master cylinder in combination with a vacuum power booster which uses vacuum and atmospheric pressure to provide power assist in actuating the master cylinder.
Master cylinders connectable to power boosters operating on vacuum pressure are known and generally comprise a piston in the master cylinder which is axially moveable by a push rod extending from the power booster. In the power booster, differential pressures acting on a diaphragm and support plate, which separate the booster housing into a control volume containing vacuum and a control volume containing a variable pressure, operatively move the push rod. A valve mechanism for the power booster is operable to admit atmospheric air pressure into the control volume containing variable pressure to actuate the power booster and move the master cylinder piston through the push rod.
With such a conventional construction, the master cylinder and the power booster are assembled as individual components and then bolted together. This tends to increase the overall length of the assembly which takes up limited space and spreads out the force carrying components requiring a heavier assembly.